++++++ Typical examples of argument parsing functions:
number nextNum(p)
register pico *p;
{
	register pico x;

	x = EVAL1(*p);
	*p = cdr(*p);
	NEEDNUM(x);
	return unBox(x);
}

bool nextBool(p)
register pico *p;
{
	register pico x;

	x = EVAL1(*p);
	*p = cdr(*p);
	return  isNil(x) ?  NO : YES;
}

pico nextVar(p)
register pico *p;
{
	register pico sym;

	sym = car(*p);
	*p = cdr(*p);
	NEEDSYM(sym);
	CHECKSYM(sym);
	return sym;
}

++++++ Other often used argument parsing functions:
void *nextDynamo(p)
register pico *p;

void *nextPtr(p)
register pico *p;

void nextColor(p,col)
register pico *p;
RGBColor *col;

StringPtr nextString(p,buf)
register pico *p;
register StringPtr buf;

void nextPoint(p,pt)
register pico *p;
register Point *pt;

void nextRect(p,r)
register pico *p;
Rect *r;

ProcPtr nextProc(p, def, foo)
register pico *p, *def;
ProcPtr foo;
